Many individuals with ongoing headache can benefit from a
thorough physical therapy evaluation of the jaw and its surrounding tissues.
The temporomandibular joint (TMJ) and its muscles and surrounding soft tissue,
may be contributing factors for some headaches. Headaches involving the facial
area, the forehead, the sides of the head or over the temporomandibular joint
itself could indicate TMJ and/or jaw muscle involvement. Headaches that are
exacerbated by chewing, yawning, or talking are also indications. Patients who
have a dental history of clenching or grinding their teeth, especially at
night, with increase in headaches upon arising in the morning, should be
assessed.
There is much confusion over proper terminology when it
comes to the jaw, even within the medical profession. You may have been told
you have TMJ, TMJD (temporomandibular joint dysfunction), or cranio-facial
dysfunction, to mention a few. These terms are confusing. Some refer to the
joint alone, some also include the jaw musculature and soft tissue, and others
include the upper cervical spine.
The jaw is not a simple hinge joint. It moves in a 4:1:1
ratio of 4 parts opening to 1 part lateral excursion (lateral movement) to 1
part protrusion (forward movement). It is suspended from the muscles of
mastication (the muscles we use to chew). This delicate balance can be
disrupted to the point of causing symptoms which contribute to headaches.
Poor posture is one of the leading causes of disorders
involving the jaw and its muscles according to Mariano Rocabado, PhD; a world
renowned physical therapist who has studied the jaw for 35 years.� A forward head position leads to a change in
the resting position of the mandible (the jaw bone) and the tongue---lowering
both. This changes not only the occlusion (contact) of the teeth, but
significantly affects the muscles of mastication. Sit up tall and feel how your
teeth meet. Now really slouch. Do you see how your teeth hit differently?
The resting position of the jaw is such that the front
third of the tongue should rest on the roof of the mouth with the tip of the
tongue just behind (without touching) the top front teeth. Your teeth should be
slightly apart and your mouth closed. In this position, you will breathe
through your nose. This normally occurs with good posture. Slouch and see how
the teeth tend to separate and the tongue position drops into the mandible.
This leads to increased use of accessory respiratory muscles (the muscles in
the upper chest and shoulders) and decreased use of the diaphragm.
With proper posture we open our mouths primarily with the
help of gravity and, to a lesser degree, from the supra-hyoid muscles (located
under the chin and in the throat area). In the forward head position, these
muscles are strained. They contract to open the mouth so they can resume their
proper resting length. Now the muscles that close the mouth (located in our
cheeks and temple areas) are strained and they contract to resume their resting
position. We have a tug of war (called "parafunction ") occurring.
This can lead to muscle spasms and trigger points.
Trigger points seem to occur more often in the muscles
closing the jaw than those that open it. Trigger points in the temporalis (a
muscle that closes the jaw and is located along the side of the head) radiate
and can contribute to headaches along the eyebrow, the side of the head and to
our upper teeth. Trigger points in the masseter (another muscle that closes the
jaw and is located in the cheek) can radiate to the eyebrow, sinus area, and
our upper or lower back teeth.
Facial asymmetry gives us input on balance between the jaw
and muscles. This imbalance has been researched in relationship to one-sided
headaches. We look at asymmetry not only from the front view but from the side
as well. There is a higher incidence of asymmetry in patients with painful
craniomandibular disorders, unilateral headaches and history of head injury.1
Hypermobility (excessive movement in their joints) can
occur also. It can stress the joint itself, the disc, the ligaments, muscles
and sometimes can cause the joint to lock. Systemic hypermobility occurs in
females more than males by a 3:1 ratio. With a combination of hypermobility, trauma,
and parafunction, symptoms are more likely to occur.2
What happens if we have a cold, allergies, etc? We breathe
through our mouth. This leads to dropping the jaw and a forward head position
so we can open up the lower airway. The results of this are the equivalent of
sitting with very poor posture.
Improper teeth contact leads to strain and imbalance in
the joints themselves. If unresolved, the muscles become involved. Evaluation
by a trained dentist may be useful in this case.
Grinding, clenching, chewing gum, fingernail or pencil
biting or even resting your chin on the hand can all lead to parafunction---the
tug of war mentioned earlier. These are habits to be broken. Smoking and
playing certain musical instruments (violin, clarinet) can add to parafunction.
A bite splint is meant to protect the surfaces of your teeth. However, those of
you who have bitten through it could be promoting parafunction activity instead
of treating it.
Physical therapists with a background in jaw treatment can
often help. They can evaluate posture, cervical spine mechanics, proper jaw
movement or restrictions, strength of muscles and trigger points. With this
information they can implement the appropriate treatment and work in
conjunction with your other doctors.
What can you do right now? Initially, sit up straight.
"Sit tall and lift your chest " are cues that can get you started. A
physical therapist can fine tune these techniques. Correcting posture is
extremely important and failing to do so can significantly interfere with the
effectiveness of your physical therapy treatment.
Secondly, consider your ergonomics both at home and at
work. When using a computer, the monitor, chair, mouse, and keyboard need to be
at the correct height. You need to face the monitor and not have your head
turned to the side, or looking up or down. With a laptop computer, you will
need a separate keyboard and mouse to attain this set-up. If you cradle the
telephone between your ear and your shoulder, replace it with a headset or use
a speaker phone. Sleeping on your stomach not only puts the neck in a rotated
position but can also put pressure on your jaw.
Thirdly, work toward eliminating habits such as gum
chewing, biting your nails, and resting your chin on your hand. Give this some thought.
For one patient, she found she needed to eliminate her habit of chewing on
unpopped popcorn kernels. Pay attention to any tendency toward clenching and
grinding. With these things in mind, you are working toward minimizing or
eliminating the part that the jaw and its muscles play in contributing to your
headache.
Parafunction, in addition to directly causing pain, could
contribute to headache by promoting nociceptive (pain-related) signals to enter
the brain. Migraine mechanisms could be activated or could make them more
likely to occur by sensitizing these neural structures. Either way, jaw
problems can result in pain, both directly and by aggravating more complex
headache mechanisms. Therefore, relieving the jaw disturbance can reduce the
tendency toward headaches beyond the pain in the jaw.
Finally if needed, seek out further evaluation from a
physician, dentist, and physical therapist with TMJ experience.
1.
Schokker RP, Hansson TL, Ansink BJ,Habets LLL.
Craniomandibular asymmetry in headache patients. J Craniomandibular Disord.
1990;4:205-209.
2.
Westling L, Carlsson GE, Helkima M. Background factors in
craniomandibular disorders with special reference to general joint
hypermobility, parafunction, and trauma. Craniomandib Disord. 1990;4:89-98.